The study of the early stage of Mn growth on GaAs(001)-c(4x4) surface has been performed by in situ Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy. Starting from GaAs(001) grown by molecular beam epitaxy, the surface was investigated after Mn deposition and after low temperature annealing at about 250 degrees C. The aim of this work is to understand the mechanism of Mn-As interaction and the behavior of Mn on the GaAs(001) substrate. The results demonstrate the high reactivity and mobility of Mn with the formation of compounds such as Mn subarsenicle (MnAs.), MnAs (confirmed by STM results) and, probably, GaMnAs.
